On the Complexity of Finding the Maximum Entropy Compatible Quantum State

Herein we study the problem of recovering a density operator from a set of compatible marginals, motivated by limitations of physical observations. Given that the set of compatible density operators is not singular, we adopt Jaynes’ principle and wish to characterize a compatible density operator wi...

Full description

Bibliographic Details
Main Authors: Serena Di Giorgio, Paulo Mateus
Format: Article
Language:English
Published: MDPI AG 2021-01-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/9/2/193
_version_ 1797409731540680704
author Serena Di Giorgio
Paulo Mateus
author_facet Serena Di Giorgio
Paulo Mateus
author_sort Serena Di Giorgio
collection DOAJ
description Herein we study the problem of recovering a density operator from a set of compatible marginals, motivated by limitations of physical observations. Given that the set of compatible density operators is not singular, we adopt Jaynes’ principle and wish to characterize a compatible density operator with maximum entropy. We first show that comparing the entropy of compatible density operators is complete for the quantum computational complexity class QSZK, even for the simplest case of 3-chains. Then, we focus on the particular case of quantum Markov chains and trees and establish that for these cases, there exists a procedure polynomial in the number of subsystems that constructs the maximum entropy compatible density operator. Moreover, we extend the Chow–Liu algorithm to the same subclass of quantum states.
first_indexed 2024-03-09T04:18:46Z
format Article
id doaj.art-3052e4dcfaf94ab09277ad32a2093e64
institution Directory Open Access Journal
issn 2227-7390
language English
last_indexed 2024-03-09T04:18:46Z
publishDate 2021-01-01
publisher MDPI AG
record_format Article
series Mathematics
spelling doaj.art-3052e4dcfaf94ab09277ad32a2093e642023-12-03T13:49:28ZengMDPI AGMathematics2227-73902021-01-019219310.3390/math9020193On the Complexity of Finding the Maximum Entropy Compatible Quantum StateSerena Di Giorgio0Paulo Mateus1Departamento de Matemática, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalDepartamento de Matemática, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, PortugalHerein we study the problem of recovering a density operator from a set of compatible marginals, motivated by limitations of physical observations. Given that the set of compatible density operators is not singular, we adopt Jaynes’ principle and wish to characterize a compatible density operator with maximum entropy. We first show that comparing the entropy of compatible density operators is complete for the quantum computational complexity class QSZK, even for the simplest case of 3-chains. Then, we focus on the particular case of quantum Markov chains and trees and establish that for these cases, there exists a procedure polynomial in the number of subsystems that constructs the maximum entropy compatible density operator. Moreover, we extend the Chow–Liu algorithm to the same subclass of quantum states.https://www.mdpi.com/2227-7390/9/2/193quantum Markov chainsmaximum von Neumann entropyQSZK-completeness
spellingShingle Serena Di Giorgio
Paulo Mateus
On the Complexity of Finding the Maximum Entropy Compatible Quantum State
Mathematics
quantum Markov chains
maximum von Neumann entropy
QSZK-completeness
title On the Complexity of Finding the Maximum Entropy Compatible Quantum State
title_full On the Complexity of Finding the Maximum Entropy Compatible Quantum State
title_fullStr On the Complexity of Finding the Maximum Entropy Compatible Quantum State
title_full_unstemmed On the Complexity of Finding the Maximum Entropy Compatible Quantum State
title_short On the Complexity of Finding the Maximum Entropy Compatible Quantum State
title_sort on the complexity of finding the maximum entropy compatible quantum state
topic quantum Markov chains
maximum von Neumann entropy
QSZK-completeness
url https://www.mdpi.com/2227-7390/9/2/193
work_keys_str_mv AT serenadigiorgio onthecomplexityoffindingthemaximumentropycompatiblequantumstate
AT paulomateus onthecomplexityoffindingthemaximumentropycompatiblequantumstate